Mobile base



FIG. 1 is a perspective view of the mobile base;

FIG. 2 is a top view of the mobile base;

FIG. 3 is a side veiw of the mobile base;

FIG. 4 is an end view of the mobile base;

FIG. 5 is an end view of the mobile base viewed from the end opposite that shown in FIG. 4; and,

FIG. 6 is a bottom view of the mobile base. 

I claim the ornamental design for the mobile base, as shown. 